Electrodes based on organic redox active materials attract more and more attention due to their inherent advantages such as renewability, lightness, fast charge and discharge abilities, and more environmentally friendly features, just to name a few. Among the different active organic materials investigated so far, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA), a polymer bearing persistent nitroxide radicals in the repeating unit, has become one of the most promising candidates as cathode material which exhibits fast reversible redox reactions and allows high energy storage, high redox potential and a long cycling life. However, the performances of organic batteries based on PTMA are greatly hindered by its solubility into organic electrolytes and its limited electrical conductivity. Moreover, a high content of PTMA leads to the aggregation of the active material in the electrode, resulting in inefficient electrical connections in and between PTMA particles hampering the whole capacity of PTMA to be utilized during battery operation.
To overcome those issues, He Jia, a postdoctoral researcher in the group of Jean-François Gohy has developed PTMA-based nanostructured electrodes (see scheme below) in which PTMA core-shell nanospheres wrapped by reduced graphene oxide nanosheets and carbon nanotubes are stacked in a multi-layer electrode. This design allows to get the best out of PTMA: the shell preventing the diffusion of PTMA into the electrolyte and the morphology of the electrode allowing efficient electron transfer processes and good ionic conductivity. The accordingly obtained electrodes outperform the existing technology in terms of specific capacity and cycling life. Those results have been published in Nano Energy
He Jia, Ting Quan, Xuelian Liu, Lu Ba, Jiande Wang, Fadoi Boujioui, Ran Ye, Alexandru Vlad, Yan Lu, Jean-François Gohy
"Core-shell nanostructured organic redox polymer cathodes with superior performance"
Nano Energy 2019, 64, 103949. https://doi.org/10.1016/j.nanoen.2019.103949